KR100620884B1 - Organic electroluminescent device, method of manufacturing the same, and electronic apparatus - Google Patents

Abstract

SUMMARY OF THE INVENTION An object of the present invention is to provide an organic EL device which can exhibit high brightness, high light emitting efficiency, and high lifespan characteristics in an organic light emitting layer of all colors with a simple configuration, and is also excellent in storage stability against heat and the like.

The organic EL device of the present invention has a laminate including an organic light emitting layer 60 between the anode 23 and the cathodes 50 and 52, wherein the organic light emitting layer 60 is made of a polymer light emitting material. At the same time, the cathodes 50 and 52 are alloys of magnesium with the first layer 52 composed of a fluoride or oxide of an alkali metal, a fluoride or oxide of an alkaline earth metal, or a complex or compound with an organic substance. The second layer 50 made of the organic light emitting layer 60 is included in this order.

LUMO level, organic electroluminescent device, organic light emitting layer, organic light emitting element, electron injection layer, work function

Description

ORGANIC ELECTROLUMINESCENT DEVICE, METHOD OF MANUFACTURING THE SAME, AND ELECTRONIC APPARATUS}

BRIEF DESCRIPTION OF THE DRAWINGS The schematic diagram which shows the wiring structure of the organic electroluminescent apparatus which concerns on one Embodiment of this invention.

2 is a plan view schematically showing a configuration of an organic EL device according to an embodiment of the present invention.

3 is a cross-sectional view taken along the line A-B of FIG.

4 is a cross-sectional view taken along the line C-D of FIG.

5 is an enlarged cross-sectional view of the main portion of FIG. 3;

6 is an enlarged cross-sectional view of a main portion showing a modification of the light emitting element;

7 is an enlarged cross-sectional view of a main portion showing an egg modification of the light emitting element.

8 is an enlarged sectional view of a main portion showing one modification of the light emitting element;

9 is a cross-sectional view illustrating a method of manufacturing an organic EL device according to an embodiment of the present invention in the order of steps.

10 is a cross-sectional view for explaining a step following the step shown in FIG. 9.

11 is a cross-sectional view for explaining a step following FIG. 10.

12 is a cross-sectional view for explaining a step following the step shown in FIG. 11.

FIG. 13 is a cross-sectional view for explaining a step following FIG. 12. FIG.

14 is a perspective view showing an example of the electronic apparatus of the present invention.

* Description of the symbols for the main parts of the drawings *

1: organic EL device

23: pixel electrode (anode)

50: cathode second layer

52: cathode first layer (electron injection layer)

60: organic light emitting layer

20: substrate

1000: mobile phone (electronic device)

The present invention relates to an organic electroluminescent device, a method for producing the same, and an electronic device including the organic electroluminescent device.

As an organic electroluminescent device (hereinafter referred to as an organic EL device), for example, Patent Document 1 (Japanese Patent Laid-Open No. 2001-332388) provides an organic light emitting layer between a cathode and an anode, and the organic light emitting layer is A structure formed of a polymer light emitting material is disclosed.

In the organic EL device disclosed in Patent Document 1, an organic light emitting layer is formed of a polymer light emitting material, and a cathode containing a material having a work function of 3.0 eV or less (electron volt) or less is used as the cathode. On the other hand, in an organic EL device using a low molecular weight light emitting material, an organic light emitting layer is generally composed of an electron transporting organic material having a Low Unoccupied Molecular Orbital (LUMO) level of 3.0 eV to 3.5 eV, and a cathode such as magnesium. A material with a function of about 3.5 eV is used. For example, the organic light-emitting layer is composed of tris (8-quinolinolato) aluminum (hereinafter referred to as Alq ₃ ) by adding a dopant corresponding to each color, and an LUMO level of Alq ₃ . Is 3.1 eV. On the other hand, the LUMO level of the polymer luminescent material used in the organic EL device using the polymer luminescent material is about 1.0 eV lower than that of the low molecular luminescent material of the same luminescent color. Therefore, in the polymer light emitting material, it is necessary to use a material having a relatively low work function, that is, a high reactivity, as the cathode as compared with the case of a low molecular weight light emitting material.

In addition, the LUMO level of the polymer light emitting material used for the full color organic EL device is different for each color of light emitted. In the light emitting material exhibiting B (blue) light emission, if the highest Occupied Molecular Orbital (HOMO) is the same, it is necessary to lower the LUMO level in order to increase the purity of the color. Therefore, in a polymer light emitting material exhibiting B (blue) light emission, a material having a LUMO level of about 2.0 eV has very preferable color purity. As a result of this, the LUMO level of the light emitting material showing B (blue) light emission is lower than that of the light emitting material showing G (green) light emission or the light emitting material showing R (red) light emission. Here, although calcium plays a role of promoting electron injection, when a cathode configuration including a material having a work function of 3.0 eV or less (electron volt) or less is applied to a full color organic EL device using a polymer light emitting material, Since the LUMO level of the organic light emitting layer which shows light emission of each color differs greatly, there existed a subject which cannot obtain favorable characteristic with respect to the organic light emitting layer which shows light emission of each color. For example, an organic light emitting layer showing R (red) light emission and an organic light emitting layer showing G (green) light emission have an LUMO level of about 3.3 eV, and are relatively high in efficiency and long life, but exhibit organic light emitting B (blue) light emission. The light emitting layer has a LUMO level of about 2.0 eV and relatively low efficiency and life characteristics. That is, when a common cathode is formed by using a material having a work function such as calcium of 3.0 eV or less, and the promotion of electron injection is promoted, a large difference occurs in the work function difference between the organic light emitting layer showing the respective emission colors and the cathode. do. Therefore, in particular, the balance of injection of electrons and holes in the organic light emitting layer showing B (blue) light emission is broken, and it is difficult to achieve high efficiency and high lifetime for the organic light emitting layers of all colors. In addition, when a material having a low work function, such as calcium, is used as the cathode, it is easy to react with oxygen, moisture, an organic light emitting layer, etc., and it is difficult to realize high life.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and provides an organic EL device which can exhibit high brightness, high light emission efficiency, and high lifespan characteristics in an organic light emitting layer of any color with a simple configuration, and is also excellent in storage stability against heat and the like. It aims at providing the electronic device provided with this organic electroluminescent apparatus.

MEANS TO SOLVE THE PROBLEM In order to solve the above-mentioned subject and achieve the objective, this invention is an organic electroluminescent apparatus provided with the some organic light emitting element which has a laminated body which consists of an organic light emitting layer between an anode and a cathode, The organic light emitting layer is made of a polymer light emitting material, and the plurality of organic light emitting devices includes a first organic light emitting material having a first LUMO level having the highest LUMO level among organic light emitting materials constituting the plurality of organic light emitting devices. A second organic light emitting device including one first organic light emitting device and a second organic light emitting material having a second LUMO level having the lowest LUMO level among the organic light emitting materials constituting the plurality of organic light emitting devices; The cathode is formed in common with the first organic light emitting element and the second organic light emitting element, and is a fluoride or oxide of an alkali metal, and A first layer comprising a fluoride or an oxide of an alkaline earth metal or a complex or compound with an organic substance, and a second layer containing an atom whose difference in work function and the first LUMO level are within 0.7 eV. It comprises in this order from an organic light emitting layer side.

According to a preferred aspect of the present invention, in the above invention, the first LUMO level is in the range of 3.0 eV to 3.5 eV, the second LUMO level is in the range of 2.0 eV to 2.5 eV, and the second layer This work function is characterized by containing atoms from 3.0 eV to 4.0 eV.

According to a preferred embodiment of the present invention, in the above invention, the first layer is lithium fluoride, and the difference between the work function of the at least one atom constituting the second layer and the second LUMO level is within 2.0 eV. It features.

By setting it as such a structure, the barrier at the time of inject | pouring an electron from a 2nd layer into the organic light emitting layer with the highest LUMO level among a some organic light emitting layer can be alleviated. Therefore, when applied to a full color organic EL device using a polymer light emitting material, even if the LUMO level of the organic light emitting layer showing light emission of each color is significantly different, high luminance, high light emission efficiency, Can represent light characteristics.

Moreover, by setting it as such a structure, materials, such as magnesium, which are low in reactivity compared with calcium etc. as a 2nd layer in the organic electroluminescent apparatus using a polymer light emitting material can be used. Therefore, deterioration of the organic EL device due to reaction with moisture, oxygen, organic light emitting layer, etc. can be reduced, high brightness, high light emission efficiency, high life characteristics can be exhibited, and also excellent organic storage stability against heat. The EL device can be realized.

Thus, in the organic EL device, the cathode is composed of a laminated structure of the first layer and the second layer, and the second layer is an alloy whose work function contains atoms of 3.0 eV to 4.0 eV, preferably the work function is 3.5 By constructing an alloy containing atoms of 4.0 eV to eV (electron volts), it is possible to provide an organic EL device exhibiting high brightness, high light emission efficiency, and long life regardless of the color of the organic light emitting layer. In addition, the material does not need to be different for each color of the organic light emitting layer, and the same cathode structure is obtained for each color, so that the above-described good luminance, efficiency, and lifespan characteristics can be obtained, and a very simple configuration can contribute to reduction of manufacturing cost. Done. That is, in the case where the organic light emitting layer includes an organic light emitting layer having a different color for each pixel unit, an organic EL exhibiting high brightness, high light emission efficiency, and long life characteristics even when a cathode is formed in a common structure in each organic light emitting layer. It is possible to provide a device. Examples of atoms having a work function of 3.0 eV to 4.0 eV include magnesium (work function 3.66 eV), scandium (work function 3.5 eV), yttrium (work function 3.1 eV), lanthanum (work function 3.5 eV), arsenic (work function 3.75 eV) Etc., magnesium is most preferred.

According to a preferred embodiment of the present invention, in the above invention, the second layer constituting the cathode is made of one or two or more alloys selected from an alloy of magnesium and silver, an alloy of magnesium and aluminum, and an alloy of magnesium and chromium. Can be. Since these alloys are particularly excellent in thermal stability, the storage stability of the organic EL device can be further improved.

In the organic EL device of the present invention, the second layer constituting the cathode may constitute the outermost layer of the laminate. In this case, since the outermost layer of the cathode is composed of the second layer, a top emission type organic EL device can be provided in accordance with the thickness of the second layer, particularly if the second layer is formed of a thin film. When formed into a thick film, it is possible to provide a bottom emission type organic EL device. In addition, in this specification, the organic light emitting layer side of the cathode is called the inside, and the opposite side is called the outside. In addition, even when the second layer constitutes the outermost layer of the laminate, since the second layer can be made of a material having low reactivity, the reaction of moisture, oxygen, an organic light emitting layer and the like and the cathode can be reduced, and the polymer light emission The stability and reliability of the organic EL device using the material can be further improved.

Alternatively, a transparent electrode may be provided on the outer layer side of the second layer. When the top emission type organic EL device is constituted by using the second layer of the cathode as a thin film, the resistance of the cathode may increase, resulting in a decrease in luminous efficiency. However, by providing a transparent electrode such as ITO on the outside thereof, It is possible to realize low resistance of the cathode while having light transmitting properties. In addition, since a material such as magnesium having a lower reactivity compared to calcium or the like can be used as the second layer, even when a transparent electrode is provided on the outer layer side of the second layer, the reaction between the transparent electrode such as ITO and the cathode can be reduced. The stability and reliability of the organic EL device using the polymer light emitting material can be further improved.

In addition, a protective film represented by SiO _x N _y (x, y is an integer) may be provided on the outer layer side of the second layer. In this case, there is a protective effect on the negative electrode and the storage stability is further improved. In addition, since a material such as magnesium having a lower reactivity compared to calcium or the like can be used as the second layer, even when a transparent electrode is provided on the outer layer side of the second layer, SiO _x N _y (x, y is an integer) The reaction of the displayed protective film and the cathode can be reduced, and the stability and reliability of the organic EL device using the polymer light emitting material can be further improved.

It is also possible that the second layer has a gradient in which the composition ratio of magnesium decreases toward the outer layer. Thus, by adopting the configuration in which the composition ratio of magnesium decreases toward the outside of the negative electrode, it is possible to vary the resistance of the negative electrode in the thickness direction thereof. In addition, the weight ratio of magnesium to other metals in the second layer may be, for example, about 10: 1 to 1:10. Too much magnesium may cause poor storage stability, and too little magnesium may degrade the function of the cathode. There is concern.

Moreover, the electronic device of this invention is equipped with the above-mentioned organic electroluminescent apparatus, It is characterized by the above-mentioned. As a result, it is possible to provide an electronic device having a long life and capable of bright display.

In order to solve the above problems and achieve the object, the present invention is an organic electroluminescent device having an organic light emitting device having a laminate comprising an organic light emitting layer between an anode and a cathode, the organic light emitting layer is a polymer light emitting The organic light emitting device has an organic light emitting layer having a LUMO level in the range of 2.0 eV to 2.5 eV, and the cathode comprises a first layer made of lithium fluoride, an alloy of magnesium and silver, an alloy of magnesium and aluminum, And a second layer made of one or two or more alloys selected from alloys of magnesium and chromium in this order from the organic light emitting layer.

Conventionally, it was necessary to use relatively high reactivity materials, such as calcium, as an anode with respect to the organic light emitting layer whose LUMO level exists in the range of 2.0 eV to 2.5 eV. According to the present invention, in such an arrangement, in an organic EL device using a polymer light emitting material, a material such as magnesium having a lower reactivity compared to calcium or the like can be used as the second layer. Therefore, deterioration of the organic EL device due to reaction with moisture, oxygen, organic light emitting layer, etc. can be reduced, and an organic EL device having high brightness, high light emission efficiency, high lifetime characteristics, and excellent storage stability against heat and the like can be obtained. It can be realized.

MEANS TO SOLVE THE PROBLEM In order to solve the above-mentioned subject and achieve the objective, this invention is a process of forming an anode on a board | substrate, the process of forming a functional layer containing an organic light emitting layer on the anode by a liquid phase method, Forming a cathode first layer comprising a fluoride or oxide of an alkali metal, a fluoride or oxide of an alkaline earth metal, or a complex or compound with an organic substance on the functional layer, and an alloy of magnesium and silver on the cathode first layer And forming a cathode second layer from one or two or more alloys selected from alloys of magnesium and aluminum, and alloys of magnesium and chromium.

In the case where a magnesium alloy is used as compared with the case of a magnesium single body, the reaction with, for example, lithium fluoride used in the first layer can be reduced, and the first layer is formed in the organic light emitting layer formed by the liquid phase method. Diffusion of the atoms constituting the microparticles can be reduced.

Moreover, according to the preferable aspect of this invention, the electronic device was equipped with the organic electroluminescent apparatus in any one of the above. It is characterized by the above-mentioned. According to the present invention, it is possible to provide an electronic device which can exhibit high brightness, high luminous efficiency, and high lifespan and is also excellent in storage stability against heat and the like.

<Organic electroluminescent device>

EMBODIMENT OF THE INVENTION Hereinafter, one Embodiment of the organic electroluminescent apparatus (organic EL apparatus) of this invention is described, referring drawings.

FIG. 1: is a figure which shows typically the wiring structure of the organic electroluminescent apparatus of this embodiment.

The organic EL device 1 is an active matrix display device using a thin film transistor (hereinafter abbreviated as TFT) as a switching element.

As shown in FIG. 1, the organic EL device 1 includes a plurality of scan lines 101..., A plurality of signal lines 102..., And signal lines 102 extending in a direction perpendicular to each scan line 101. Has a configuration in which a plurality of power supply lines 103... Which extend in parallel are respectively wired, and a pixel region X... Is provided near the intersections of the scanning lines 101... And the signal line 102. .

The signal line 102 is connected with a data line driving circuit 100 including a shift register, a level shifter, a video line, and an analog switch. In addition, a scan line driver circuit 80 having a shift register and a level shifter is connected to the scan line 101.

In each pixel area X, a switching TFT 112 through which a scan signal is supplied to the gate electrode through the scanning line 101, and a pixel signal supplied from the signal line 102 through the switching TFT 112. The holding capacitor 113 to be held, the driving TFT 123 to which the pixel signal held by the holding capacitor 113 is supplied to the gate electrode, and the power source line 103 through the driving TFT 123. A pixel electrode (anode) 23 through which a drive current flows from the power supply line 103 when electrically connected, a cathode including a cathode first layer and a cathode second layer 50, and this pixel electrode 23 A functional layer 110 sandwiched between the cathode and the cathode is provided. The pixel electrode 23, the cathode, and the functional layer 110 constitute an organic light emitting element (organic EL element) as a laminate.

According to this organic EL device 1, when the scanning line 101 is driven and the switching TFT 112 is turned on, the potential of the signal line 102 at that time is held in the holding capacitor 113. The on / off state of the driving TFT 123 is determined according to the state of the holding capacitor 113. Then, a current flows from the power supply line 103 to the pixel electrode 23 through the channel of the driving TFT 123, and a current flows through the functional layer 110 to the cathode second layer 50. The functional layer 110 emits light according to the amount of current flowing therethrough.

Next, the specific structure of the organic electroluminescent apparatus 1 of this example is demonstrated with reference to FIGS.

First, the planar structure of the organic EL device of this embodiment is demonstrated based on FIG. In the organic EL device 1 of this example, a pixel electrode region (not shown) in which a substrate 20 having electrical insulation and a pixel electrode connected to a switching TFT (not shown) are arranged in a matrix on the substrate 20. O), a power supply line (not shown) disposed around the pixel electrode region and connected to each pixel electrode, and a pixel portion 3 (in Fig. 2) that is substantially rectangular in plan view on at least the pixel electrode region. And a one-dot chain line border). In addition, in this invention, it is called a base including the board | substrate 20 and switching TFT, various circuits, an interlayer insulation film, etc. which are formed on this as mentioned later.

The pixel portion 3 includes the real display area 4 (in the dashed-dotted line border in FIG. 2) in the center portion, and the dummy area 5 (dotted-dotted line) arranged around the real display area 4. And the region between the two-dot chain lines). In the real display area 4, the display areas R, G, and B each having pixel electrodes are arranged in a matrix form while being spaced apart in the A-B direction and the C-D direction, respectively. Scan line driving circuits 80 and 80 are disposed on both sides of the real display area 4 in FIG. 2. These scan line driving circuits 80 and 80 are disposed below the dummy region 5.

In addition, the inspection circuit 90 is disposed above the real display region 4 in FIG. 2. This inspection circuit 90 is a circuit for inspecting the operation state of the organic EL device 1, and includes, for example, inspection information output means (not shown) for outputting inspection results to the outside, and during manufacturing or shipping. The display device can be inspected for quality and defects. This inspection circuit 90 is also disposed below the dummy region 5.

The scan line driving circuit 80 and the inspection circuit 90 are applied with their driving voltages from a predetermined power supply through the driving voltage conducting portion 310 (see FIG. 3) and the driving voltage conducting portion 340 (see FIG. 4). . In addition, the drive control signals and the drive voltages to the scan line driver circuit 80 and the inspection circuit 90 are driven from the predetermined main driver or the like which controls the operation of the organic EL device 1 and the like. 3) and the drive control signal conduction unit 350 (see FIG. 4). In addition, the drive control signal in this case is a command signal from a main driver or the like related to control when the scan line driver circuit 80 and the inspection circuit 90 output signals.

Next, the cross-sectional structure of this organic electroluminescent apparatus is demonstrated based on FIG. 3 and 4 are cross-sectional views taken along the line A-B in FIG. 2, and FIG. 5 is an enlarged view of the main portion thereof. In the organic EL device 1, as shown in Figs. 3 and 4, the substrate 20 and the sealing substrate 30 are bonded to each other through the sealing resin 40. Figs.

As the board | substrate 20, what is called a bottom emission type organic electroluminescent apparatus is a structure which emits light emission from the board | substrate 20 side, and a transparent or translucent thing is employ | adopted. For example, glass, quartz, resin (plastic, plastic film), etc. are mentioned, In particular, an inexpensive soda glass substrate is used suitably.

In addition, in the case of the so-called top emission type organic EL device, since it emits light from the side of the sealing substrate 30 which is the opposite side of the substrate 20, the substrate 20 has either a transparent substrate or an opaque substrate. Anything can be used. As an opaque board | substrate, thermosetting resin, a thermoplastic resin, etc. are mentioned besides not only giving insulation processes, such as surface oxidation, to metal sheets, such as ceramics and stainless steel, such as alumina.

As the sealing substrate 30, for example, a plate member having electrical insulation property can be employed. In particular, in the case of the top emission type, a transparent substrate such as glass, quartz, resin or the like is adopted as the sealing substrate 30. The sealing resin 40 is made of, for example, a thermosetting resin or an ultraviolet curable resin, and particularly preferably made of an epoxy resin which is a kind of thermosetting resin.

In addition, a circuit portion 11 including a driving TFT 123 for driving the pixel electrode 23 is formed on the substrate 20, and a light emitting element is provided thereon. As shown in Fig. 5, the light emitting element comprises a pixel electrode 23, a functional layer 110 mainly composed of an organic light emitting layer 60 (see Fig. 1), and a cathode first layer (electron injection layer). A cathode composed of 52 and a cathode second layer 50 is laminated in this order.

The pixel electrode 23 functions as an anode for supplying holes to the organic light emitting layer 60. The pixel electrode 23 has ITO (indium tin oxide) or indium oxide oxide in the case of a bottom emission type. Transparent conductive materials, such as a zinc-type amorphous transparent conductive film (Indium Zinc Oxide: IZO (trademark)) (made by Idemitsu Kosan Corporation), are used. In addition, in the case of a top emission type, it is not limited to such a transparent conductive material, For example, light reflective or opaque conductive materials, such as aluminum (Al) and silver (Ag), can also be used.

As the organic light emitting layer 60, a known polymer light emitting material capable of emitting fluorescence or phosphorescence is used. Specifically, polyfluorene derivative (PF), polyparaphenylene vinylene derivative (PPV), polyphenylene derivative (PP), polyparaphenylene derivative (PPP), polyvinylcarbazole (PVK), polythiol Offen derivatives, polydialkylfluorenes (PDAF), polyfluorenebenzothiadiazoles (PFBT), polyalkylthiophenes (PAT), poly (2,7- (9,9-di-ene-octylfluorene) -(1,4-phenylene-((4-methylphenyl) imino) -1,4-phenylene-((4-methylphenyl) imino) -1,4-phenylene)) (PFM), poly ( 2,7- (9,9-di-ene-octylfluorene)-(1,4-phenylene-((4-methoxyphenyl) imino) -1,4-phenylene-((4-meth Methoxyphenyl) imino) -1,4-phenylene)) (PFMO), poly (2,7- (9,9-di-ene-octylfluorene-3,6-benzothiadiazole) (F8BT) Polysilanes such as polymethylphenylsilane (PMPS), etc. are preferably used, etc. In addition, perylene-based dyes, coumarin-based dyes, rhodamine-based dyes, rubrene, perylene, 9,10-diphenyl, and the like are used for these polymer materials. Anthracene, tetraphenylbutadiene, na Low molecular materials such as nile red, coumarin 6 and quinacridone may be used by doping.

As the polymer light emitting material emitting blue light, for example, PFM represented by [Formula 1] and PFMO represented by [Formula 2] are suitably used, and LUMO levels are 2.1 eV and 2.0 eV, respectively. As the polymer light emitting material emitting green light, for example, F8BT represented by [Formula 3] is suitably used, and the LUMO level is 3.4 eV. Moreover, as a polymeric light emitting material which emits red light, for example, PAT represented by [Formula 4] or poly (2,5-diaalkoxy-pi-phenylenevinylene) represented by [Formula 5] (PO-PPV) ) Is suitably used, and LUMO levels are 3.3 eV and 3.2 eV, respectively.

[Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

The term "polymer" means a polymer having a molecular weight greater than the so-called "low molecular weight" of several hundred degrees, and in the above-mentioned polymer material, an oligomer having a molecular weight of 10,000 or less in addition to a polymer having a molecular weight of 10,000 or more generally called a polymer. oligomers called oligomers are included. In this embodiment, in order to perform full color display, the organic light emitting layer 60 corresponding to R (red), G (green), and B (blue) is juxtaposed in one pixel.

In addition, in this embodiment, the hole injection / transport layer 70 (refer FIG. 5) can be provided between the pixel electrode 23 and the organic light emitting layer 60 as needed. By providing this hole injection / transport layer, the electrons which move in the organic light emitting layer 60 are blocked efficiently, and the probability of recombination of the electrons and holes in the organic light emitting layer 60 increases. A material having a low injection barrier from the pixel electrode 23 and a high hole mobility is suitably used for the hole injection / transport layer 70. As such a material, a polythiophene derivative, a polypyrrole derivative, etc., or these doping bodies etc. are used, for example. Specifically, 3,4-polyethylenedioxythiophene is dispersed in a dispersion of 3,4-polyethylenedioxythiophene / polystyrenesulfonic acid (PEDOT / PSS), that is, polystyrene sulfonic acid as a dispersion solvent, and further dispersed in water. Dispersions and the like.

As shown in Figs. 3 to 5, the cathode second layer 50 has an area larger than the total area of the real display area 4 and the dummy area 5, and is formed to cover each of them. This cathode second layer 50 is composed of an alloy containing a work function of 3.0 eV to 4.0 eV, and in this embodiment, an alloy of magnesium (Mg) and silver (Ag) is used. In addition, an alloy of magnesium (Mg) and aluminum (Al), or an alloy of magnesium (Mg) and chromium (Cr) may be used. However, the alloy with chromium (Cr) is difficult to deposit, so that it is stable and manufactured. In view of efficiency, an alloy of magnesium (Mg) and silver (Ag) is suitable. Moreover, as for the thickness of the cathode 2nd layer 50, 50 nm or more is preferable, and is comprised in about 200 nm in this embodiment. In addition, as the work function used for the cathode second layer 50 as an atom of 3.0 eV to 4.0 eV, scandium (work function 3.5 eV), yttrium (work function 3.1 eV), lanthanum (work function 3.5 eV), arsenic ( A work function of 3.75 eV) may be used.

Next, in this embodiment, in order to improve the electron injection efficiency from the cathode second layer 50 to the organic light emitting layer 60, the cathode first layer (electron injection) between the cathode second layer 50 and the organic light emitting layer 60. Layer) 52 is provided. The negative electrode first layer (electron injection layer) 52 is a fluoride of an alkali metal, and is specifically composed using lithium fluoride (LiF). In addition, for example, an oxide of an alkali metal, a chloride of an alkali metal, or It can also comprise using a fluoride or oxide of an alkaline earth metal, or a complex or compound with an organic substance.

For example, sodium fluoride (NaF), potassium fluoride (KF) and the like as alkali metal fluorides, and lithium oxide (Li ₂ O), sodium oxide (Na ₂ O) and potassium oxide (K) as oxides of alkali metals. ₂ O) and the like, and fluorides of alkaline earth metals include magnesium fluoride (MgF ₂ ), calcium fluoride (CaF ₂ ), and the like, and oxides of alkaline earth metals include magnesium oxide (MgO) and calcium oxide (CaO). As the complex or compound of the formula A, the general atom MA _n B _m (n: is the central atom M) is represented by M as the central atom composed of a metal element, M the chelate ligand composed of an organic material, and the neutral ligand composed of the organic material. The organometallic compound represented by valency, m: natural number) can be illustrated, and as such a complex, complexes of various structures, such as a chelate complex and a crown ether complex, can be used. As for the thickness of the cathode 1st layer (electron injection layer) 52 comprised from these compounds etc., about 0.1 nm-about 10 nm are preferable, In this embodiment, it is comprised about 2 nm.

In the present embodiment, the organic light emitting layer 60 is formed between the pixel electrode (anode) 23 as the stacked structure of the cathode first layer (electron injection layer) 52 and the cathode second layer 50. The negative electrode which pinches is comprised. Here, in the case of the bottom emission type, the cathode configuration is not particularly a problem, but in the case of the top emission type, the cathode composed of the cathode first layer (electron injection layer) 52 and the cathode second layer 50 is thinned ( For example, the thickness is about 5 nm).

Next, the structure of the circuit part for driving this light emitting element is demonstrated based on FIG. The circuit part 11 is provided below the said light emitting element as shown in FIG. This circuit part 11 is formed on the board | substrate 20, and comprises a base body. In other words, a base protective layer 281 mainly composed of SiO ₂ is formed on the surface of the substrate 20 as a base, and a silicon layer 241 is formed thereon. On the surface of the silicon layer 241, a gate insulating layer 282 mainly composed of SiO ₂ or SiN is formed. In the silicon layer 241, the region overlapping the gate electrode 242 with the gate insulating layer 282 interposed therebetween as the channel region 241a. In addition, the gate electrode 242 is a part of the scanning line 101 (not shown). On the other hand, a first interlayer insulating layer 283 mainly composed of SiO ₂ is formed on the surface of the gate insulating layer 282 covering the silicon layer 241 and forming the gate electrode 242.

In the silicon layer 241, a low concentration source region 24lb and a high concentration source region 241S are provided on the source side of the channel region 241a, while a low concentration drain region (on the drain side of the channel region 241a). 241c and a high concentration drain region 241D have a so-called Light Doped Drain (LDD) structure, among which the high concentration source region 241S has a gate insulating layer 282 and a first interlayer insulating layer 283. The source electrode 243 is connected to the source electrode 243 via a contact hole 243a that opens over the source hole 243. The source electrode 243 is the power source 103 (see FIG. 1, the position of the source electrode 243 in FIG. 5). Extends in the vertical direction to the ground plane, on the other hand, the highly-concentrated drain region 241D is a contact hole 244a opening over the gate insulating layer 282 and the first interlayer insulating layer 283. Is connected to the drain electrode 244 having the same layer as the source electrode 243 There is.

The upper layer of the first interlayer insulating layer 283 on which the source electrode 243 and the drain electrode 244 are formed is covered with, for example, a second interlayer insulating layer 284 mainly composed of an acrylic resin component. As the second interlayer insulating layer 284, materials other than an acrylic insulating film, for example, silicon compounds such as SiN and SiO ₂ may be used. Thus, when the silicon compound with high gas barrier property, especially a silicon nitrogen compound, is used for the 2nd interlayer insulation layer 284, when the board | substrate main body 20 is made into the resin substrate with high moisture permeability, In addition, invasion of oxygen, moisture, and the like into the organic light emitting layer 60 from the substrate side can be prevented, and the life of the light emitting element can be extended. A pixel electrode 23 made of ITO is formed on the surface of the second interlayer insulating layer 284, and the pixel electrode 23 is a contact hole 23a provided in the second interlayer insulating layer 284. It is connected to the drain electrode 244 via. That is, the pixel electrode 23 is connected to the high concentration drain region 241D of the silicon layer 241 via the drain electrode 244.

Further, an N-channel type or a P-channel constituting a TFT (driving circuit TFT) included in the scan line driver circuit 80 and the inspection circuit 90, that is, an inverter included in a shift register, for example, among these drive circuits. The TFT of the type has the same structure as the driving TFT 123 except that it is not connected to the pixel electrode 23.

On the surface of the second interlayer insulating layer 284 on which the pixel electrode 23 is formed, a bank structure composed of the pixel electrode 23, the lyophilic control layer 25, and the organic bank layer 221 is provided. The lyophilic control layer 25 is for example intended to the lyophilic material such as SiO ₂ as a main component, is formed of the organic bank layer 221, for example, acrylic or polyimide and the like. The hole injection / transport layer 70 and the organic light emitting layer 70 are formed on the pixel electrode 23 inside the opening 25a provided in the lyophilic control layer 25 and the opening 221a surrounded by the organic bank layer 221. 60) are stacked in this order. In addition, the "lyophilic" of the lyophilic control layer 25 in this example shall mean a thing with high lyophilicity compared with materials, such as an acryl and polyimide which comprise the organic bank layer 221 at least. . The layer up to the second interlayer insulating layer 284 on the substrate 20 described above constitutes the circuit portion 11.

The organic EL device 1 having the above configuration has a polymer light emitting material between a cathode composed of a cathode second layer 50 and a cathode first layer (electron injection layer) 52 and a pixel electrode 23 as an anode. While the organic light emitting layer 60 is formed by being sandwiched, the cathode second layer 50 is made of an alloy of magnesium. In this manner, the cathode is constituted as a laminated structure of the cathode first layer (electron injection layer) 52 and the cathode second layer 50, and the cathode second layer 50 is made of an alloy of magnesium to thereby form an organic light emitting layer. Irrespective of the color of (60), that is, even in the organic light emitting layer 60 of any color, it exhibits high brightness, high light emission efficiency, and long life characteristics. More specifically, the above configuration enables good electron injection into the organic light emitting layer 60 made of PFM or PFMO having an LUMO level of about 2.0 eV, and F8BT, PAT or PO- having an LUMO level of about 3.3 eV. Electrons can be injected into the organic light emitting layer 60 made of PPV. Therefore, the balance of injection of electrons and holes can be achieved in all the organic light emitting layers 60 showing light emission of each color, thereby showing high brightness and high light emission efficiency.

In addition, the magnesium alloy used in the present embodiment is less likely to be oxidized and excellent in storage stability as compared with the case where the negative electrode second layer 50 of the negative electrode is composed of magnesium alone. In addition, the materials do not need to be different for each color of the organic light emitting layer 60, and a common cathode configuration is obtained for each color, so that the above-described good luminance, efficiency, and life characteristics can be obtained, and the manufacturing cost is reduced with a very simple configuration. Will also be able to contribute. That is, even when the organic light emitting layer 60 includes the organic light emitting layer 60 of a different color for each pixel unit, the high brightness is achieved by a simple configuration in which a cathode is formed in a common structure to the organic light emitting layer 60 of each color. It is intended to exhibit high luminous efficiency and long life characteristics.

In addition, in the organic EL device having a plurality of organic light emitting layers that emit light in a plurality of light emitting colors, the LUMO level of the material constituting the organic light emitting layer having the highest LUMO level among the plurality of organic light emitting layers and the cathode second layer 50 are formed. The work function of the material is about the same, and the cathode first layer (electron injection layer) 52 is formed between the organic light emitting layer 60 and the cathode second layer 50, and the cathode first layer (electron injection layer) 52. ) Is preferably composed of a fluoride of an alkali metal, an oxide of an alkali metal, a fluoride or an oxide of an alkaline earth metal, or a complex or compound with an organic substance. In addition, it is preferable that the work function difference between the LUMO level of the material constituting the organic light emitting layer having the lowest LUMO level among the organic light emitting layers and the material constituting the cathode second layer 50 is within 0.7 eV. With such a configuration, the barrier when injecting electrons from the cathode second layer 50 to the organic light emitting layer having the highest LUMO level and the lowest organic light emitting layer among the plurality of organic light emitting layers can be alleviated. In particular, the above effects can be enhanced by using a semiconductor having a band gap and an insulator as the material of the cathode first layer (electron injection layer) 52. When the work function of the material constituting the cathode second layer 50 is 0.7 eV or more higher than the LUMO level of the material constituting the organic light emitting layer having the lowest LUMO level among the plurality of organic light emitting layers, the LUMO level of the plurality of organic light emitting layers is high. The electron injection to the highest organic light emitting layer cannot be performed efficiently. When the work function of the material constituting the cathode second layer 50 is 0.7 eV or more lower than the LUMO level of the material constituting the organic light emitting layer having the lowest LUMO level among the plurality of organic light emitting layers, the moisture, oxygen, and organic light emitting layers Reaction of the 60 and the like and the cathode second layer 50 deteriorates the stability and reliability of the organic EL device using the polymer light emitting material.

More specifically, since the LUMO level of the organic light emitting layer having the highest LUMO level is about 3.3 eV and the LUMO level of the organic light emitting layer having the lowest LUMO level is about 2.0 eV, the cathode second layer 50 has a work function of 3.66 eV. When magnesium phosphorus is used, such a condition is satisfied. If the work function difference between the LUMO level of the organic light emitting layer having the lowest LUMO level and the cathode second layer 50 is within 2.0 eV, lithium fluoride is used as the cathode first layer (electron injection layer) 52 to optimize its film thickness. This can alleviate the barrier when electrons are injected into the organic light emitting layer 60 from the cathode second layer 50. Therefore, the balance of injection of electrons and holes can be achieved in all the organic light emitting layers 60 showing light emission of each color, thereby showing high brightness and high light emission efficiency.

In this configuration, in an organic EL device using a polymer light emitting material, a material such as magnesium having a lower reactivity compared to calcium or the like can be used as the cathode second layer 50. Therefore, deterioration of the organic EL device due to reaction with moisture, oxygen, the organic light emitting layer 60, etc. can be reduced, high brightness, high light emission efficiency, high life characteristics can be exhibited, and organic excellent in storage stability against heat and the like. The EL device can be realized. In addition, in the case of the top emission type, even when the cathode made of the cathode first layer (electron injection layer) 52 and the cathode second layer 50 is thinned (for example, about 5 nm thick), Since the two layers 50 can be made of a material having low reactivity, the reaction of moisture, oxygen, the organic light emitting layer 60 and the like can be reduced, and stability and reliability of the organic EL device using the polymer light emitting material can be reduced. I can improve it more.

Moreover, in the said embodiment, although the 2nd negative electrode layer 50 is arrange | positioned at the uppermost layer of the light emitting element which consists of laminated bodies, you may provide a transparent electrode in the outer side of the said 2nd negative electrode layer 50 side. That is, when the top emission type organic EL device is constituted by using the cathode second layer 50 as a thin film as shown in Fig. 6, the resistance of the cathode second layer 50 is increased to cause a decrease in luminous efficiency. Although there exists a possibility, by providing the transparent electrode 53, such as ITO, on the outer side, the fall of the resistance value of the said cathode side electrode can be implement | achieved with transparency.

In addition, as shown in FIG. 7, an insulating film 54 represented by SiO _x N _y (x, y is an integer) may be provided on the outer side of the cathode second layer 50. In this case, there is a protective effect on the cathode second layer 50, and the storage stability is further improved.

In addition, as the cathode second layer 50, a material such as magnesium having a lower reactivity than that of calcium or the like can be used, so that it is represented by a transparent electrode 53 such as ITO or SiO _x N _y (x and y are integers). The reaction between the insulating film 54 and the cathode can be reduced, and the stability and reliability of the organic EL device using the polymer light emitting material can be further improved.

In addition, as shown in Fig. 8, the negative electrode second layer 50 may be configured to have a gradient in which the composition ratio of magnesium decreases toward the outer layer. Thus, by adopting the configuration in which the composition ratio of magnesium decreases toward the outside of the negative electrode, it is possible to vary the resistance of the negative electrode in the thickness direction thereof. In addition, the weight ratio of magnesium and other metals in the negative electrode second layer 50 may be, for example, about 10: 1 to 1:10, and when too much magnesium is poor in storage stability, too little magnesium may cause There is a possibility that the function may be degraded.

<Method for producing organic electroluminescent device>

Next, an example of the manufacturing method of the said organic electroluminescent apparatus 1 is demonstrated with reference to FIGS. Here, each sectional drawing shown in FIGS. 9-13 corresponds to sectional drawing of the A-B line | wire in FIG.

First, as shown in FIG. 9A, a base protective layer 281 is formed on the surface of the substrate 20. Next, the amorphous silicon layer 501 is formed on the underlying protective layer 281 using ICVD, plasma CVD, or the like, and then crystal grains are grown by laser annealing or rapid heating to form a polysilicon layer. Make it.

Subsequently, as shown in Fig. 9B, the polysilicon layer is patterned by photolithography to form island-like silicon layers 241, 251, and 261. Figs. Among them, the silicon layer 241 is formed in the display area, and constitutes the driving TFT 123 connected to the pixel electrode 23, and the silicon layers 251 and 261 are included in the scan line driver circuit 80. P-channel and N-channel TFTs (driving circuit TFTs) are respectively constructed.

Next, the gate insulating layer 282 is formed by a silicon oxide film having a thickness of about 30 nm to 200 nm on the entire surfaces of the silicon layers 241, 251, and 261 and the underlying protective layer 281 by plasma CVD, thermal oxidation, or the like. ). Here, when the gate insulating layer 282 is formed using the thermal oxidation method, the silicon layers 241, 251, and 261 can also be crystallized to make these silicon layers polysilicon layers.

When channel doping is performed on the silicon layers 241, 251, and 261, for example, boron ions are implanted at a dose of about 1x10 ¹² cm ^-2 at this timing. As a result, the silicon layers 241, 251, and 261 become low concentration P-type silicon layers having an impurity concentration (calculated as impurities after activation annealing) of about 1x10 ¹⁷ cm ^-3 .

Next, ion implantation is selected to a part of the channel layer of the P channel TFT and the N channel TFT

A mask is formed and phosphorus ions are ion implanted in this state at a dose of about 1 × 10 ¹⁵ cm ^-2 . As a result, high concentration impurities are introduced into the patterning mask by self alignment, and as shown in Fig. 9C, the high concentration source regions 241S and 261S and the high concentration in the silicon layers 241 and 261 are shown. Drain regions 241D and 261D are formed.

Next, as shown in FIG. 9C, the entire surface of the gate insulating layer 282 is formed of a metal, such as a doped silicon or silicon compound film, an aluminum film, a chromium film, or a tantalum film. A gate electrode forming conductive layer 502 is formed. The thickness of this conductive layer 502 is about 500 nm. Subsequently, as shown in Fig. 9 (d) by the patterning method, the gate electrode 252 for forming the P-channel driving circuit TFT, the gate electrode 242 for forming the pixel TFT, and the N-channel driving are formed. The gate electrode 262 which forms a circuit TFT is formed. In addition, the driving control signal conducting unit 320 (350) and the first layer 121 of the cathode power wiring are also formed at the same time. In this case, the drive control signal conducting portion 320 (350) is arranged in the dummy region (5).

Then, the gate electrode 9 (242, 252, 262) as shown in (d) for use as a mask, the phosphorus ions with respect to the silicon layer (241, 251, 261) of about 4 × 10 ¹³ ㎝ ^-2 dose Ion implantation in amount. As a result, low concentration impurities are introduced into the gate electrodes 242, 252, and 262 in a self-aligned manner, and as shown in FIG. 9D, the low concentration source regions 24 lb and 26 lb in the silicon layers 241 and 261. And low concentration drains 241c and 261c. In addition, low concentration impurity regions 251S and 251D are formed in the silicon layer 251.

Next, as shown in Fig. 10E, an ion implantation selection mask 503 covering a portion other than the P-channel driver circuit TFT 252 is formed. Using this ion implantation selection mask 503, boron ions are implanted into the silicon layer 251 at a dose of about 1.5 × 10 ¹⁵ cm ⁻² . As a result, since the gate electrode 252 constituting the TFT for the P-channel driving circuit also functions as a mask, high concentration impurities are doped self-aligned in the silicon layer 251. Therefore, the lightly doped impurity regions 251S and 251D are counter-doped to become source and drain regions of the P-channel driver circuit TFT.

Next, as shown in FIG. 10 (f), the first interlayer insulating layer 283 is formed over the entire surface of the substrate 20, and the first interlayer insulating layer 283 is formed using a photolithography method. By patterning the contact holes, contact holes C are formed at positions corresponding to the source and drain electrodes of each TFT.

Next, as shown in Fig. 10G, a conductive layer 504 made of a metal such as aluminum, chromium, or tantalum is formed to cover the first interlayer insulating layer 283. Figs. The thickness of this conductive layer 504 is approximately 200 nm to 800 nm. Thereafter, in the conductive layer 504, the region 240a in which the source electrode and the drain electrode of each TFT should be formed, the region 310a in which the driving voltage conduction part 310 (340) should be formed, and the cathode power wiring The patterning mask 505 is formed to cover the region 122a where the two layers should be formed, and the conductive layer 504 is patterned to show the source electrodes 243, 253, and 263 shown in FIG. 11H. Drain electrodes 244, 254 and 264 are formed. Next, as shown in Fig. 11 (i), the second interlayer insulating layer 284 covering the first interlayer insulating layer 283 on which they are formed is formed of a polymer material such as acrylic resin, for example. The second interlayer insulating layer 284 is preferably formed to a thickness of about 1 to 2 mu m. Further, SiN, also possible to form the second interlayer insulating film by the SiO ₂ and, 200㎚ As the film thickness of the SiN, as the film thickness of SiO ₂ is preferably formed of a 800㎚.

Next, as shown in Fig. 11 (j), the portion of the second interlayer insulating layer 284 corresponding to the drain electrode 244 of the driving TFT is removed by etching to form the contact hole 23a. Thereafter, a conductive film serving as the pixel electrode 23 is formed so as to cover the entire surface of the substrate 20. By patterning this transparent conductive film, as shown in FIG. 12 (k), the pixel electrode 23 which is in contact with the drain electrode 244 is formed through the contact hole 23a of the second interlayer insulating layer 284. At the same time, a dummy pattern 26 of a dummy region is also formed. 3 and 4, these pixel electrodes 23 and dummy patterns 26 are collectively referred to as the pixel electrodes 23.

The dummy pattern 26 is configured not to connect to the lower metal wiring via the second interlayer insulating layer 284. In other words, the dummy pattern 26 is arranged in an island shape and has a shape substantially the same as that of the pixel electrode 23 formed in the real display area. Of course, the structure different from the shape of the pixel electrode 23 formed in the display area may be sufficient. In this case, the dummy pattern 26 also includes at least the upper portion of the driving voltage conduction portion 310 (340).

Next, as shown in Fig. 12 (l), a lyophilic control layer 25 is formed on the pixel electrode 23, the dummy pattern 26, and on the second interlayer insulating film. In addition, the lyophilic control layer 25 is formed in a part of the pixel electrode 23 to open, and hole movement from the pixel electrode 23 is possible in the opening 25a (see FIG. 3). . On the contrary, in the dummy pattern 26 in which the opening 25a is not provided, the insulating layer (liquid control layer) 25 serves as a hole movement shielding layer so that hole movement does not occur. Subsequently, BM is formed in the concave portion formed between the two other pixel electrodes 23 in the lyophilic control layer 25. Specifically, it forms into a film by the sputtering method using the metal chromium with respect to the said recessed part of the lyophilic control layer 25. FIG.

Next, as shown in FIG. 12 (m), the organic bank layer 221 is formed so as to cover the predetermined position of the lyophilic control layer 25, specifically, the BM. As a specific method of forming an organic bank layer, what melt | dissolved resist, such as an acrylic resin and a polyimide resin, in a solvent is apply | coated by various coating methods, such as a spin coating method and a dip coating method, and an organic layer is formed, for example. In addition, the constituent material of the organic layer may be any one so long as it is not dissolved in a solvent of ink described later and is easily patterned by etching or the like.

Next, the organic layer is etched simultaneously by photolithography or the like to form the bank openings 221a of the organic material, and the organic bank layer 221 having a wall surface is formed in the openings 221a. In this case, the organic bank layer 221 may include at least the upper portion of the driving control signal conducting unit 320.

Next, the area | region which shows a lyophilic property and the area | region which shows liquid repellency is formed in the surface of the organic bank layer 221. FIG. In this embodiment, each area is formed by a plasma processing step. Specifically, the plasma processing step includes a preliminary heating step, a top surface of the organic bank layer 221, a wall surface of the opening 221a and a pixel electrode. A lip ink process for making the upper surface of the electrode surface 23c and the lyophilic control layer 25 of (23) lyophilic, an ink repelling process for making the upper surface of the organic bank layer and the wall surface of the opening part liquid-repellent, The cooling process is provided.

In other words, the substrate (substrate 20 including a bank or the like) is heated to a predetermined temperature, for example, about 70 to 80 ° C., and then plasma treatment using oxygen as a reaction gas in an atmospheric atmosphere as a pro-inking step (O _2). Plasma treatment). Next, a plasma treatment (CF ₄ plasma treatment) using methane tetrafluoromethane as a reaction gas in an atmospheric atmosphere as an ink repelling step, and then cooling the heated substrate to room temperature for lipophilic and foot repellent The liquidity is given to a predetermined point.

In the CF ₄ plasma treatment, the electrode surface 23c and the lyophilic property of the pixel electrode 23 are used.

Although somewhat influenced also on the control layer 25, since ITO, which is the material of the pixel electrode 23, and SiO ₂ , TiO ₂ , which are the constituent materials of the lyophilic control layer 25, lack affinity for fluorine, The lyophilic properties are maintained without the hydroxyl group given in the lipophilic process being substituted with a fluorine group.

Next, as shown in Fig. 13 (n), a hole injection / transport layer forming step for forming the hole injection / transport layer 70 is performed. In the hole injection / transport layer forming step, an inkjet method is particularly suitably employed as the droplet ejection method. That is, by the inkjet method, the hole injection / transport layer forming material is selectively disposed on the electrode surface 23c to apply this. Thereafter, drying treatment and heat treatment are performed to form a hole injection / transport layer 70 on the pixel electrode 23. As a material for forming the hole injection / transport layer 70, for example, a solution obtained by dissolving the above PEDOT: PSS in a polar solvent such as isopropyl alcohol is used.

Here, in the formation of the hole injection / transport layer 70 by this inkjet method, first, a hole injection / transport layer forming material is filled in an inkjet head (not shown), and the discharge nozzle of the inkjet head is used as the lyophilic control layer 25. Opposite to the electrode surface 23c positioned in the opening 25a formed in the opening, the droplets of which the amount of liquid per drop is controlled from the discharge nozzle are moved while the inkjet head and the substrate (substrate 20) are relatively moved. ) Next, the droplet after discharge is dried and the hole injection / transport layer 70 is formed by evaporating the dispersion medium and the solvent contained in the material.

At this time, the droplet discharged from the discharge nozzle spreads on the electrode surface 23c subjected to the lyophilic treatment and is filled in the opening 25a of the lyophilic control layer 25. On the other hand, droplets do not splash and adhere on the upper surface of the liquid repellent organic bank layer 221. Therefore, even if the droplets deviate from the predetermined discharge position and a part of the droplets spans the surface of the organic bank layer 221, the surface does not wet the droplets, and the splashed droplets do not open the openings of the lyophilic control layer 25 ( 25a). Moreover, after this hole injection / transport layer formation process, it is preferable to perform in inert gas atmosphere, such as nitrogen atmosphere and argon atmosphere, in order to prevent the oxidation and moisture absorption of various forming materials and the formed element.

Next, an organic light emitting layer forming process is performed to form the organic light emitting layer 60. In this step, similarly to the formation of the hole injection / transport layer 70 described above, the inkjet method, which is a droplet ejection method, is suitably employed. That is, the organic light emitting layer forming material is discharged onto the hole injection / transport layer 70 by the inkjet method, and thereafter dried and heat treated to thereby form the opening 221a formed in the organic bank layer 221, that is, on the pixel region. The organic emission layer 60 is formed. In addition, in this organic light emitting layer forming step, in order to prevent re-dissolution of the hole injection / transport layer 70, a nonpolar solvent which does not dissolve in the hole injection / transport layer 70 is used as a solvent of the material ink used in forming the organic light emitting layer. use. In addition, when forming the organic light emitting layer 60, it is performed for every color.

Next, a cathode first layer forming process is performed to form the cathode first layer (electron injection layer) 52 on the organic light emitting layer 60. Although this cathode 1st layer (electron injection layer) 52 is comprised using lithium fluoride (LiF) specifically as a fluoride of an alkali metal, In addition, for example, oxides of an alkali metal, or an alkaline earth metal It can also comprise using a fluoride or an oxide, or a complex or compound with an organic substance. In particular, lithium fluoride is preferable because it can be formed at a low temperature and is a semiconductor and an insulator having a band gap. As the method for forming the cathode first layer (electron injection layer) 52, a known method such as vacuum deposition can be adopted.

Subsequently, as shown in Fig. 13 (o), in order to form the cathode second layer 50, a cathode second layer forming step is performed by vapor deposition. In this step, an alloy of magnesium is formed on the entire surface of the exposed portion of the cathode first layer (electron injection layer) 52 by vacuum evaporation. The alloy of magnesium (Mg) and silver (Ag) is preferably magnesium oxide in which magnesium precipitated on the surface during production reacts with oxygen to improve gas barrier properties against water and oxygen. In addition, the work function used as the cathode second layer is scandium (work function 3.5 eV), yttrium (work function 3.1 eV), lanthanum (work function 3.5 eV), arsenic (work function 3.75 eV) as atoms of 3.0 eV to 4.0 eV. ) May be used. And a sealing process is performed in order to form the sealing substrate 30 last. In this sealing process, the sealing board 30 and the board | substrate 20 are sealed with the adhesive agent 40, inserting the desiccant 45 inside the sealing board 30. As shown in FIG. In addition, it is preferable to perform this sealing process in inert gas atmosphere, such as nitrogen, argon, and helium.

In addition, when magnesium alloy is used as compared with the case where magnesium is composed of a single element, the reaction with, for example, lithium fluoride, which is used for the negative electrode first layer (electron injection layer) 52 in the negative electrode, can be reduced. The diffusion of the atoms constituting the cathode first layer (electron injection layer) 52 into the organic light emitting layer 60 can be reduced. In particular, when the organic light emitting layer 60 is formed by a liquid phase method such as a droplet ejection method, a liquid organic light emitting layer forming material containing a solvent is discharged onto the hole injection / transport layer 70, and then dried and heat treated. Form by removing solvent. When the solvent is removed in this manner, micropores are formed in the organic light emitting layer 60. For this reason, the atom which comprises the cathode 1st layer (electron injection layer) 52 becomes easy to diffuse in the organic light emitting layer 60. FIG. In the organic light emitting layer 60 thus formed, a thin film of lithium fluoride is formed as the cathode first layer (electron injection layer) 52, and then the cathode second layer 50 is composed of magnesium alloy, so that the droplet ejection method or the like. Atoms constituting the cathode first layer (electron injection layer) 52 in accordance with the organic light emitting layer 60 formed by the liquid phase method diffuse into the organic light emitting layer 60 and further suppress the problem of unstable characteristics of the organic EL element. You can.

<Example>

Next, the luminous efficiency and lifetime characteristics of the organic EL device 1 were evaluated.

Specifically, as a structure of the cathode, Comparative Example 1 in which the first layer was formed of calcium, the second layer was made of aluminum, and Comparative Example 2 in which the first layer was formed of lithium fluoride / calcium, and the second layer was made of aluminum And luminous efficiency and lifetime of each color (red (R), green (G), blue (B)) for Example 1 in which the first layer is formed of lithium fluoride and the second layer is formed of an alloy of magnesium and silver. The characteristics were compared respectively. PFM is used as the polymer light emitting material emitting blue (B), and the LUMO level is 2.1 eV. In addition, F8BT is used as the polymer light emitting material emitting green (G), and the LUMO level is 3.4 eV. In addition, PAT is used as a polymer light emitting material that emits red (R), and the LUMO level is 3.3 eV. The results are shown in Table 1 (luminescence efficiency) and Table 2 (life characteristics). In addition, in each table | surface, when the red (R) of the comparative example 1 is set to "1" about luminous efficiency, and the blue (B) of the comparative example 2 is set to "1" about lifetime characteristic, Relative values are shown.

TABLE 1

Comparative Example 1 Comparative Example 2 Example 1 R One 0.3 One G One 1.1 1.3 B 0.2 One 1.1

TABLE 2

Comparative Example 1 Comparative Example 2 Example 1 R One One 1.5 G One 0.8 1.9 B 0.01 One One

As can be seen from Table 1, the light emitting efficiency of blue (B) is decreased in the negative electrode configuration of Comparative Example 1, and the light emitting efficiency of red (R) is decreased in the negative electrode configuration of Comparative Example 2, while the negative electrode configuration of Example 1 Has been found to exhibit excellent luminous efficiency for all colors. In addition, as can be seen from Table 2, the life of blue (B) is short in the negative electrode configuration of Comparative Example 1, the life of green (G) is short in the negative electrode configuration of Comparative Example 2, while the negative electrode configuration of Example 1 Shows a high lifetime for all colors. That is, the organic EL device 1 of the present embodiment in which the cathode is formed of an alloy of lithium fluoride (first layer) and magnesium and silver (second layer) has excellent light emission in each of the above-mentioned colors even if the cathode configuration is common to each color. It was found to exhibit efficiency and lifespan characteristics.

<Electronic device>

 Next, the specific example of the electronic device provided with the organic electroluminescent apparatus of this invention is demonstrated. The electronic device of this invention has said organic electroluminescent apparatus as a display part, The thing specifically, shown in FIG. 14 is mentioned. 14 is a perspective view illustrating an example of a mobile telephone. In Fig. 14, reference numeral 1000 denotes a mobile telephone body, and reference numeral 1001 denotes a display unit using the organic EL device described above. Since the electronic apparatus shown in FIG. 14 is provided with the display part which has the said organic electroluminescent apparatus, a long display lifetime and a bright display can be obtained.

According to the present invention, an organic EL device and an electronic device including the organic EL device, which can exhibit high brightness, high light emission efficiency, and high lifespan characteristics in an organic light emitting layer of all colors with a simple configuration, and also have excellent storage stability against heat and the like. Can provide.

Claims (12)

An organic electro luminescence device comprising a plurality of organic light emitting elements having a laminate comprising an organic light emitting layer between an anode and a cathode. The organic light emitting layer is made of a polymer light emitting material, The plurality of organic light emitting elements includes a first organic light emitting element including a first organic light emitting material having a first LUMO level having the highest LUMO level among the organic light emitting materials constituting the plurality of organic light emitting elements, and the plurality of organic light emitting elements. A second organic light emitting element comprising a second organic light emitting material having a second LUMO level having the lowest LUMO level among the organic light emitting materials constituting the organic light emitting element, The cathode is formed in common in the first organic light emitting device and the second organic light emitting device, and is a complex or compound of an fluoride or oxide of an alkali metal, a fluoride or an oxide of an alkaline earth metal, or an organic substance. An organic layer comprising, in this order, a first layer comprising a second layer comprising an atom having a difference between a work function and the first LUMO level within 0.7 eV; Electroluminescence device. The method of claim 1, The first LUMO level is in the range of 3.0 eV to 3.5 eV, The second LUMO level is in the range of 2.0 eV to 2.5 eV, And said second layer comprises atoms having a work function of 3.0 eV to 4.0 eV. The method according to claim 1 or 2, The first layer is lithium fluoride, And a difference between the work function of the at least one atom constituting the second layer and the second LUMO level is within 2.0 eV. The method of claim 1, And said second layer is made of one or two or more alloys selected from alloys of magnesium and silver, alloys of magnesium and aluminum, and alloys of magnesium and chromium. The method of claim 1, The said 2nd layer comprises the outermost layer of the said laminated body, The organic electroluminescent apparatus characterized by the above-mentioned. The method of claim 1, An organic electroluminescent device, characterized in that a transparent electrode is provided on the outer layer side of the second layer. The method of claim 1, An organic electroluminescent device, characterized in that a protective film represented by SiO _x N _y (x, y is an integer) is provided on the outer layer side of the second layer. The method of claim 1, An organic electroluminescence device, characterized in that the second layer has a gradient in which the composition ratio of magnesium decreases toward the outer layer. The method of claim 1, In the second layer, the organic electroluminescence device, characterized in that the weight ratio of magnesium and other metals is 10: 1 to 1:10. Substrate, An organic electroluminescent device comprising an organic light emitting element having a laminate comprising an organic light emitting layer between an anode and a cathode, The organic light emitting layer is made of a polymer light emitting material, The organic light emitting device has an organic light emitting layer having a LUMO level in the range of 2.0 eV to 2.5 eV, The cathode comprises, in this order, a first layer made of lithium fluoride and a second layer made of one or two or more alloys selected from an alloy of magnesium and silver, an alloy of magnesium and aluminum, and an alloy of magnesium and chromium. An organic electroluminescent device, characterized in that it comprises. An electronic device comprising the organic electroluminescent device according to any one of claims 1, 2, and 10. Forming an anode on the substrate, Forming a functional layer including an organic light emitting layer on the anode by a liquid phase method; Forming a cathode first layer comprising a fluoride or oxide of an alkali metal, a fluoride or oxide of an alkaline earth metal, or a complex or compound with an organic substance on the functional layer; A method for producing an organic electroluminescent device, comprising: forming a cathode second layer from one or two or more alloys selected from an alloy of magnesium and silver, an alloy of magnesium and aluminum, and an alloy of magnesium and chromium on the anode first layer.

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